Remove `xblock-utils` dependency

[Agrendalath]

Parent ticket: https://github.com/openedx/axim-engineering/issues/915

This repository is using the xblock-utils package, which has been deprecated and migrated to within the xblock package.

In this ticket, we will:

• [ ] Make sure the repository is using xblock version 1.8.1 or above. Upgrade the version if required, preferably via the make upgrade command.
• [ ] Remove the xblock-utils package.
• [ ] Find and replace all the xblockutils.* imports with xblock.utils.*. Provide the fallback mentioned below.
• [ ] Make sure all the test cases are passing.
• [ ] Test the XBlock.

Example fallback for imports:

try:
    from xblock.utils.resources import ResourceLoader
    from xblock.utils.settings import ThemableXBlockMixin, XBlockWithSettingsMixin
except ModuleNotFoundError:  # For backward compatibility with releases older than Quince.
    from xblockutils.resources import ResourceLoader
    from xblockutils.settings import ThemableXBlockMixin, XBlockWithSettingsMixin

[kdmccormick]

Additional tasks discovered in https://github.com/open-craft/xblock-poll/pull/127, which I had to abandon over time constraints:

• [ ] Delete integration tests
• [ ] Remove Makefile entries, etc. regarding integration tests
• [ ] Remove bok-choy, selenium, and (maybe?) xblock-sdk from dev requirements
• [ ] Add XBlock[django] as a base requirement
• [ ] Recompile requirement .txt files

[kdmccormick]

@Agrendalath I noticed that 1.14.0 will fix the log warnings--thanks! When the upgrade lands in edx-platform master, assuming it's not risky, would you mind backporting it to Redwood? I think this would be a nice touch to make the release easier for operators to work with.

[Agrendalath]

@kdmccormick, do you mean backporting the version bump to Redwood? Because this XBlock is compatible with all releases back to at least Palm.

[kdmccormick]

@kdmccormick, do you mean backporting the version bump to Redwood?

Yes